The early 1970s were a difficult time for British public galleries. Faced with runaway inflation and rising oil prices, the Heath government had left them to fend for themselves. Realising that collections would have to be publicised rather than just shown, gallery directors appointed their first marketing officers: typically, nicely brought-up girls who had worked in education departments, and had no idea of commercial life.
Jenkins, herself a nicely brought-up girl, had acquired this knowledge along the way. The daughter of a cash-strapped army officer, she had supported herself since leaving school, latterly in advertising. Tall, stylish and effortlessly grand, she was running MacKay's account for Grant's whisky - a brand for which she was to retain a lifelong affection - when she spotted the hole in the art market. Moving to Freeman's in 1972, she became the first British account handler to deal specifically with museums and galleries.
The effect was galvanising. According to Sir Roy Strong, then Director of the Victoria & Albert Museum,
Exhibition advertising really began with [Jenkins]. There were no slogans before her. If you were having a show, you might ask the HMSO to do you a poster; but the idea of a campaign as such just didn't exist.
Together, Jenkins and Strong invented "The V&A Family": a winsome group shown clasping things bought in the museum's shop over the forgettable legend, "Spend a Day at the V&A".
From these tentative beginnings, exhibition advertising grew more sophisticated under Jenkins's steady hand. It was she who persuaded institutions like the Whitechapel Art Gallery and British Museum to pool their tiny budgets, beating London Underground down on prices and buying poster space in bulk. In Jenkins's mind, these arts bodies weren't in competition with each other; on the contrary, their safety lay in numbers. And, while she is best remembered for specific campaigns - from the earliest shows at the Hayward to the National Gallery's magisterial "Rembrandt: the master and his workshop" in 1992, not long before her retirement - she insisted that museums had a duty to publicise their permanent collections as well. Success in art advertising wasn't only measured in pounds and pence, although she was proud always to have made a profit for her last agency, Saatchi's.
A populariser rather than a populist, Jenkins found later developments in arts marketing hopelessly vulgar. The V&A's "Ace Caff with Quite a Nice Museum Attached" ad made her snort, though it was a Saatchi campaign. Her views on the Tate's corporate branding process were unprintable. Jenkins's taste had been honed over three years spent in Rome in the 1960s, and culture was a serious business.
Whatever her later misgivings about it, Jenkins remained an elder statesman of the art world. On any given night, you might find a gaggle of ambassadors and museum directors crammed into her tiny kitchen in Wyndham Place; although you might equally find art history students and army sergeants. Jenkins' unquestioning sociability was a vital part of her success, and of the awe in which she was held.
It had played a less certain role in her earlier career. Recruited by MI6 in 1951, she was sent by banana boat to Trinidad, at the age of 22, to report on the colony's growing independence movement. Her reference, written by an elderly brigadier, had ended with the words, "She is an excellent dancer, though not so good as her mother." Sizing up a local politician, Albert Gomes, she discovered that he, too, was a good dancer. Unfortunately, he was also an independence agitator and Communist. When the pair were seen once too often on the floor of the Perseverance Club in Port-of-Spain, Jenkins was sacked and sent home.
She remained, to the end, a mass of engaging contradictions. Constitutionally hard up, she flew to Rome twice a year to have her hair done and to shop on the Via Condotti. (The advertising guru Paul Arden - a colleague at Saatchi's - once asked her whether she bought her clothes at MaxMara. Jenkins fixed him with a basilisk stare and said, "I beg your pardon?") She was a socialist who pronounced off "orf" and across "acrorse"; a heartfelt Roman Catholic who refused to take the Sacrament because it meant confessing a 40-year-old love affair.
Dying of cancer in a London clinic, she claimed to be fed up with life; then she sat back as a manicurist, called to her bedside, painted her nails Jungle Red.
Stella Fay Jenkins, advertising account director: born Chatham, Kent 25 May 1928; died London 31 January 2005.